Link to How-To: Editing footage from multiple video cameras?
That description in the manual covers most points.
Align your clips so they all match the clapper board marking.
Add a Multi cam strip above them.
Split the preview into 4 previews by dragging from the corner of the editor area.
In the preview sidebar set the Channel number to match channels 0-3. 0 will show the final edit.
If your computer is fast enough to run everything in accurate fps, all is fine.
If not, select all video strips.
In the preview - view menu - go to proxies.
Select Set up.
Check 25%
Check Overwrite.
Select rebuild.
Select - Scene render size - Proxy 25% And repeat for all previews.
Now it should play at a constant frame rate.
Select the Multicam strip.
In the Sequencer sidebar, you can see the options.
The channel selector you can change the channel of the active/selected strip(white outline).
If you click on the number buttons underneath, you'll make a split in the multicam strip, and switch to the channel number you pressed.
If you set the playhead to the beginning, having the multicam strip selected, and you hit play, you can also do &quot;live&quot; switching by using the number keys ex. 1 is switch to channel 1.
I did a patch to improve the multicam user experience, but it has not been committed: https://developer.blender.org/D10521